I Thought It Was Love (1991) on Netflix

Tommaso and Cecilia are two young Neapolitan boyfriends. They lead a regular life with their usual friends: he has a restaurant in Borgo Marinari next to Castel dell'Ovo, near the bookshop of their friend Amedeo, celibate and bigoted, with a teenage sister named Chiara who is in love with Tommaso. The marriage of the two is approaching, but Cecilia's jealousy risks ruining everything: during a moment of intimacy she thinks she hears Tommaso pronounce the name of another woman, Elena; on another occasion he takes him by the hair when he learns that another woman has been looking for him on the phone. Finally, while choosing the favors he makes a scene thinking about the ghosts of these hypothetical rivals, until he tells him, over the intercom, that he intends to leave him, not to marry again and to disappear.